In transmission line multiplexing technology that bundles and uses two or more transmission lines as one logical line to achieve broadband communication compared to the case of using a single transmission line, processing is being performed to divide packets over plural lines on the transmitting side in order to effectively use a bandwidth.
In Patent Literature 1, a network system is disclosed in which packets are distributed for transmitting to plural connections of a MPLS (Multi-Protocol Label Switching) network, and those plural connections are used as a single logical line. Patent Literature 2 also discloses a packet transmission method that improves the efficiency of bandwidth usage by dividing as necessary non real-time communication packets having a large packet size when real-time communication packets and non real-time communication packets having different packet sizes are mixed together on multiple logical lines.